LONDON -- After Linda Davies reported to police that her 15-year-old daughter had been raped, it took three months -- plus two dozen phone calls and a threat of legal action -- before police questioned the suspect, a 28-year-old neighbor.

"I gave police his name, address, mobile phone number, car registration -- everything but his passport," said Davies, 44, a strong-minded mother of two daughters. "I was basically begging them. He lived five minutes away from us."

The suspect was finally arrested but acquitted at a trial in which the judge told the jury that he was "in a way a man of good character" because his previous criminal convictions, for possession of stolen goods and marijuana, did not involve violence.

Davies was furious at the judge, who also instructed the jurors to ignore the victim's young age, and at police, who lost cellphone records that contradicted the defendant's account.

"This has shattered us," Davies said. "We felt like the whole system was against us."

Davies said she was stunned to learn that her daughter's case was the rule, not the exception. According to government statistics, only 5.7 percent of rapes officially recorded by police in England and Wales end in a conviction.

In Britain, a nation whose justice system has been used as a model around the globe, government officials and women's rights activists agree that rape goes largely unpunished.

Solicitor General Vera Baird, who oversees criminal prosecutions in England, estimated that 10 to 20 percent of rapes are brought to authorities' attention. According to government figures, 14,000 cases a year are reported and 19 out of 20 defendants walk free.

"There will never be proper female equality and appropriate dignity afforded to one-half of the population if it's possible to rape somebody and get away with it," said Baird, one of the highest-ranking women in the British government.

Thousands of victims each year once chose not to go to police because of shame, women's advocates say. Now, the advocates say, the bigger reason is that rape victims feel the system is stacked against them.

A 2005 report commissioned by the police found a "culture of skepticism" in the justice system when it came to rape cases, and recommended shifting the focus from seeking reasons not to believe the accuser to gathering evidence to support the charge.

Lisa Longstaff, spokeswoman for the London-based group Women Against Rape, said rape cases are "not a priority" for busy police and prosecutors and, as a result, "so few rapists get locked up that those who do feel unlucky rather than guilty."

Even some cases that do end in a guilty verdict stir outrage. Last year, a judge sentenced a 24-year-old man to two years in prison for having sex with a 10-year-old after concluding that the girl had "dressed provocatively."

Patricia Scotland, England's first female attorney general since the job was created in the 15th century, appealed that sentence. It was increased to four years.

Longstaff and others said that despite advances toward equality, sex crimes run up against a persistent societal bias -- pronounced in the male-dominated police and judicial system -- that women have only themselves to blame.

Julie Bindel, a feminist activist and writer, said there has been a huge cultural shift since the 1950s and 1960s toward acceptance that unmarried women can have casual sex.

But, she said, "women are allowed that bit more freedom as long as men behave. When men choose not to, it comes right back at women: 'What did you do to stop him? What was it about you that he chose you to rape?' "

A Claim of Mixed Signals

In a TV ad paid for by the police of Manchester, England, that began airing this month, a young man and woman are enjoying a pleasant evening, at first.

But after they drink alcohol, dance and kiss, the man leads the woman out of the nightclub, yanks her pants down and forces her to have sex against a wall as she cries, "No. No. . . . Get off of me."

In the ad, the man is locked up. In real life, according to dozens of interviews with victims and experts, this is exactly the kind of case that ends in an acquittal, if it goes to court at all.

Acquittals are often won on the "mucky sex" defense -- that the man got mixed signals from the woman and what resulted really wasn't rape.

Danielle West, 30, who reported to police that she was raped after a boozy office Christmas party in December 2006, said police seemed uninterested in her case once she said she had been drinking heavily.

West, an American who manages a team of Web analysts in London, turned visibly upset as she recounted her story in a quiet corner of a coffee shop. She said police, rather than giving her the benefit of the doubt, seemed "hostile" and intent on trying to "trip me up."

"I was constantly fighting to get someone to believe me," said West, who has a young daughter. She said a female officer flatly told her that she believed no crime had been committed and that West had simply gotten "drunk and had a shag," a British term for sex.

"I couldn't believe it," West said. "If you had told me this was modern-day Kabul, okay. But London?"

She has since hired a lawyer to file a formal complaint against the police. A police spokesman said it was "inappropriate" to comment on West's case because an investigation into her complaint was ongoing.

Debaleena Dasgupta, a lawyer who represents West, said another client filed a complaint against an officer who allowed a man accused of rape to go on vacation before police took his statement. In yet another case, a 38-year-old woman from Cornwall said police interviewed, weeks apart, two men whom she accused of raping her one night, giving them time to coordinate their stories.

Improving Investigations

"We have got to do better," said John Yates, assistant commissioner of the London Metropolitan Police. He described the rape conviction rate as "appalling" and said police had "to build better cases."

Rape cases are particularly challenging, he said, because women often delay reporting, there are no eyewitnesses and alcohol blurs the victim's recollection of details.

"Every crime requires good first steps," he said, such as interviewing witnesses immediately and grabbing footage off the millions of closed-circuit security cameras in Britain. "If you get the first steps wrong, it's hard to re-create it."

About 25 percent of reports of assault and 75 percent of homicides lead to someone being found guilty. In the 1970s, the rape conviction rate ran at more than 30 percent. The difference now is that there are far more "date rape" cases -- like the one depicted in the Manchester police ad.

Kerim Fuad, a barrister who has defended more than 100 men accused of rape, including the defendant in the Davies case, said most of the time the defendant and the accuser know each other and the jury must decide whom to believe.

A woman always has a right to say no, he said, but when she goes into a man's bedroom late at night after they have both been drinking, juries may have a hard time voting to send a man to prison.

Fuad declined to speak about specific cases, but he said he has been surprised by some "not guilty" verdicts. He said jurors have been shown compelling evidence -- such as blood at the scene or internal injury to the woman -- and still not returned a guilty verdict.

It is illegal in Britain to interview jurors -- even after a verdict. But public opinion polls show that a sizable proportion -- a quarter to a third -- of Britons say a rape victim is responsible for the attack if she is drunk or wearing "sexy" clothes.

"As many as one in two young men believe there are some circumstances when it's okay to force a woman to have sex," said Conservative Party leader David Cameron, citing studies.

"In my mind," he said, "this is an example of moral collapse."

'Let Down by the System'

Around the world, rapists are rarely punished. In the United States, 13 percent of rape reports end in a conviction. In many developing and Muslim countries, women's activists say many victims don't even report gang or stranger rapes because it is so difficult to win convictions. Reporting has even led to victims being charged with adultery or sentenced to public lashings for "mingling" with men.

In wealthier Western countries, women are told that this crime shouldn't be hidden and are counseled to take a stand against men who force them into unwanted sex.

"But what is the point," asked Davies, when in the end the prosecutor often has a poorly put-together case, the defense contends that the sex was consensual -- at least mostly -- and the jury is told to be sure beyond a reasonable doubt?

"When we do report it, we are completely let down by the system," she said.

Governments collect crime statistics differently and international comparisons are difficult, but England's conviction rate stands out as particularly low. That has led to calls to reform a tradition-bound judicial system where judges and attorneys in criminal courtrooms still wear white wigs.

Police, prosecutors and judges are increasingly being trained specifically to deal with sex crimes. Judges are being urged to allow wider use of expert testimony so that, for example, a rape trauma expert could explain why a victim might delay reporting. Now, the defense often uses that delay to attack a victim's credibility.

Until a few months ago, prosecutors were barred from interviewing victims and met them only on the day of the trial.

Ken McDonald, the head of the Crown Prosecution Service, called this restriction "mad." He said it dated back centuries to the days when witnesses stuck straw in their shoes outside courtrooms to indicate their testimony could be bought.

'I Was Happy Before'

Linda Davies's daughter, who asked that her first name not be used, said her courtroom experience two years ago still keeps her awake at night, crying. The 5-foot-2, brown-haired student met the prosecutor minutes before the trial. She had no warning that the defense would insinuate that she had a tarnished reputation and agreed to the sex for pocket cash -- and that the prosecutor wouldn't object.

She was floored when Judge Jonathan Van Der Werff, as recorded in a transcript, told the jury that the defendant was "in a way a man of good character" and that it should disregard her age, "in case it's worrying you." Now retired, Van Der Werff declined an interview request.

The defendant, who is unemployed, never took the stand. The teenager said he had told her he was 19; police later told her he was 28.

The girl said in an interview that the man invited her to his apartment. "He told me he wanted to get his dog to take on a walk," she said, covering her face. She had initially thought he was nice and kissed him. But then, she said, "he told me he would do something really bad to me" if she refused sex. "I couldn't push him off and I was trying really hard," said the girl, who weighs 90 pounds.

She said she wished police had interviewed someone at the local supermarket where she stood sobbing after the attack, or had asked to see the store's video surveillance tapes.

"This has made me a different person," she said, her voice fading and her brown eyes looking into the distance. "I was happy before. Now I am angry.

"I feel I didn't get justice. If I ever have kids and this happened to them, I wouldn't tell them to report it."

Researchers Jill Colvin and Karla Adam in London and staff researcher Robert E. Thomason in Washington contributed to this report.